1. Field of the Invention
This invention relates to a molded composition based on synthetic surfactants, plasticizers and fillers, preferably in bar form, of which the foam quality is improved by an addition of talcum.
2. Discussion of Related Art
It is known that synthetic surfactants, like soaps produced from fatty acid soaps, can be converted by kneading, milling, extrusion, cutting and bar pressing into a form suitable for transportation or for application and that noodles, granules, bars and handy cakes of toilet soap can be produced in this way.
To this end, the known high-foaming anionic surfactants are normally mixed with plasticizers, fillers and extenders which provide for easier molding and which ensure better dimensional stability.
Unfortunately, many of these substances have an adverse effect on the foaming behavior of the synthetic compositions, more especially their initial foaming behavior. The foam volume, foam stability and foam quality of synthetic compositions are often unsatisfactory.
Accordingly, there has been no shortage of attempts to overcome this deficiency by using suitable surfactant mixtures and additives. An overview of the production of synthetic compositions and known additives can be found in JAOCS, Vol. 59, No. 10 (October 1982), pages 442 to 448. In addition, it is known that builder salts, layer silicates (bentonites) and calcium-binding zeolites can be added to detergent bars which are used for washing laundry.
It is known from DE 39 39 579 A1 that an addition of alkali metal aluminium silicates of the zeolite type improves the moldability and foaming behavior of certain synthetic compositions.
U.S. Pat. No. 4,150,001 describes detergent bars for washing laundry which contain up to 60% by weight of builder salts, 1 to 40% by weight of alkaline earth metal phosphates and talcum to reduce the tendency towards shrinkage.
EP 0 266 200 A2 describes a solid detergent bar of nonionic surfactants for prewashing laundry which may also contain clays, talcum and calcites as carrier component.
It has now been found that an addition of talcum can distinctly improve the moldability and the initial foaming behavior, foam volume and fine-bubble character of the foam in the application of synthetic compositions.
Accordingly, the present invention relates to a molded synthetic composition containing at least 25% by weight of synthetic surfactants and at least 30% by weight of non-surface-active organic plasticizers and fillers which contains from 5 to 30% by weight of talcum to improve its foaming properties and its moldability.
The synthetic surfactants present may be ionic and nonionic surfactants, although high-foaming anionic surfactants should be predominantly used, i.e. more than 15% by weight of such surfactants should be used. Ampholytic, zwitterionic and nonionic surfactants may be additionally present in quantities of up to 10% by weight.
Anionic surfactants containing a linear C12-18 alkyl or acyl group and a sulfonate or sulfate group in the form of their alkali metal, magnesium, ammonium or alkanolammonium salts are preferably used in a quantity of 25 to 50% by weight as high-foaming synthetic surfactants. Suitable anionic surfactants may be represented, for example, by general formulae I to IV below:
R1xe2x80x94SO3(xe2x88x92)M(+)xe2x80x83xe2x80x83(I)
R2Oxe2x80x94(EO)xxe2x80x94SO3(xe2x88x92)M(+)xe2x80x83xe2x80x83(II)
R3CO(A)xe2x80x94CH2xe2x80x94CH2SO3(xe2x88x92)Mxe2x80x83xe2x80x83(III)
R4O CO(B)xe2x80x94SO3(xe2x88x92)M(+)xe2x80x83xe2x80x83(IV)
In these formulae, R1, R2 and R4 are linear alkyl or alkenyl groups containing 10 to 18 carbon atoms while R3CO is a linear acyl group containing 12 to 18 carbon atoms, (EO) is a (C2H4O) or (C3H6O) group, x is 0 or a number of 1 to 6, (A) is oxygen or a CH3N group, (B) is a group (CnH2n), where n=1 to 3, or a group (xe2x80x94CHxe2x80x94CH2xe2x80x94COO(xe2x88x92)M(+)) and M is an alkali metal, Mg+2, ammonium or alkanolammonium cation.
Suitable surfactants of formula I are alkane sulfonates and olefin sulfonates; suitable surfactants of formula II are alkyl sulfates and alkyl ether sulfates; surfactants of formula III are acyl isethionates and acyl taurides; suitable surfactants of formula IV are sulfocarboxylic acid esters, for example sulfoacetates, sulfopropionates or sulfosuccinates. Preferred anionic surfactants are, above all, acyl isethionates, sulfosuccinates and mixtures thereof.
Besides anionic surfactants, amphoteric or zwitterionic surfactants may be present in the compositions in small quantities of up to 10% by weight. Suitable amphoteric surfactants are, for example, C12-18 alkyl aminopropionic acid or C12-18 alkyl aminoacetic acid. Suitable zwitterionic surfactants are, for example, C12-18 alkyl dimethyl carboxymethyl aceto-betaine and C12-13 acyl amidopropyl dimethyl acetobetaine.
Nonionic surfactants may also be present in the synthetic compositions according to the invention in relatively small quantities of 1 to 10% by weight. Suitable nonionic surfactants are products of the addition of ethylene oxide onto C10-22 fatty alcohols, onto C10-22 fatty acids, onto fatty acid monoglycerides, onto sorbitan fatty acid monoesters, onto fatty acid triglycerides or onto methyl glucoside fatty acid monoesters. Particularly suitable nonionic surfactants are alkyl (oligo)glycosides corresponding to the formula R5O(C6H10O5)yxe2x80x94H, where R5 is an alkyl group containing 8 to 18 carbon atoms, (C6H10O)y is a glucoside unit and y is its average degree of oligomerization of 1 to 5. Alkyl (oligo)glycosides such as these are commercially available, for example under the trademark Plantaren(copyright) 2000 CSUP or Plantacare(copyright) 2000 CSUP.
Talcum is a hydrated magnesium silicate with the theoretical composition 3MgOxc2x74SiO2xc2x7H2O or Mg3 (Si4O10)xc2x7(OH)2 which may also contain hydrated magnesium aluminium silicate in a quantity capable of making up an Al2O3 content of up to 12% by weight.
The particle diameter (equivalent spherical diameter) of the talcum should be in the range from 0.5 to 50 xcexcm. In general, talcum qualities containing no more than 5% by weight of particles smaller than 1 xcexcm in size and no more than 5% by weight of particles larger than 50 xcexcm in size have proved to successful. The percentage content of particles larger than 40 xcexcm in diameter (sieve residue) is at most 2% by weight; the mean particle diameter is preferably 5 to 15 xcexcm.
The impurity content should be no more than 1.6% by weight Fe2O3, 1% by weight CaO and 1% by weight non-combined water (drying loss at 105xc2x0 C.). The content of hydrated magnesium aluminium silicate may be as high as 60% by weight (expressed as Al2O3 up to 12% by weight).
The synthetic composition according to the invention is preferably free from fatty acid soaps, although quantities of less than 10% by weight of fatty acids in the form of the soap are tolerable.
Suitable non-surface-active organic plasticizers and refatting agents are, for example,
free fatty acids containing 16 to 22 carbon atoms,
fatty alcohols containing 16 to 22 carbon atoms and
fatty acid esters such as, for example, hydrogenated fats (triglycerides), waxes, glycerol monostearate, glycol distearate,
paraffins.
Suitable organic fillers are, for example, carbohydrates (starch, dextrins, sugars), sorbitol, mannitol, urea, proteins and protein hydrolyzates and polyethylene glycols (Carbowax(copyright)).
The synthetic compositions according to the invention preferably contain 30 to 50% by weight of non-surface-active organic plasticizers and fillers from the group of C12-22 fatty alcohols, free C16-22 fatty acids, fatty acid esters, paraffins and carbohydrates or mixtures thereof.
In addition, the synthetic compositions according to the invention may contain the following ingredients in small quantities of up toxe2x80x94in allxe2x80x945% by weight as further auxiliaries:
complexing agents
antimicrobial agents, preservatives
dyes, pigments (TiO2), opacifiers and flatting agents
perfumes
salts, for example Na2SO4, NaH2PO4, Na5P3O10 
antioxidants
dermatological or cosmetic active substances (for example skin moisturizers, such as Na lactate, pyrrolidone carboxylic acid, glycerin).
The synthetic compositions according to the invention may also contain water. However, the water content of the synthetic composition should be below 10% by weight. In a preferred embodiment, the synthetic composition contains about 5 to 10% by weight of water.
In one particularly preferred embodiment, the synthetic compositions according to the invention contain:
30 to 40% by weight of anionic surfactants from the group of acyl ise-thionate salts, sulfosuccinic acid monoalkyl ester salts or mixtures thereof,
30 to 50% by weight of organic plasticizers and fillers from the group of fatty alcohols, free fatty acids, fatty acid esters, paraffins and starch,
10 to 30% by weight of talcum and
5 to 10% by weight of water.
The molded synthetic compositions according to the invention may be produced by any of the methods normally used for such products, the combination according to the invention of synthetic surfactants and talcum giving a particularly moldable composition which is plastic when hot and hard after cooling. The molded products have a smooth surface which, even after wetting with water, dries again without becoming soft.
Conventional processes for mixing or homogenizing, kneading and optionally milling, extruding, optionally pelleting, extruding, cutting and bar pressing, which are described for example in JAOCS, Vol. 59, No. 10 (October 1982), 442-448, may also be used for the production of the synthetic soap compositions according to the invention.
The following procedure has proved successful for the production of synthetic toilet soaps based on the synthetic composition according to the invention:
The meltable components, for example the fatty acid, the fatty alcohol, the alkyl (oligo)glucoside and the meltable or liquid plasticizers, are melted and heated at a temperature of 60 to 90xc2x0 C. in a heatable kneader or mixer. The anionic surfactant, for example the C12-18 acyl isethionate salt, optionally the sulfosuccinate and the starch and other components which do not melt at 60 to 90xc2x0 C. and optionally the water are then added and the whole is mixed or kneaded at a temperature of around 70xc2x0 C.
Further homogenization can be achieved by pressing the composition repeatedly through sieves and finally extruding it at a head temperature of 40 to 70xc2x0 C. to form a strand which is cut into uniform pieces. Finally, the pieces may be converted into the final shape in a molding press.
Instead of being extruded into a strand, the composition may also be extruded through a multiple-bore die which results in the formation of noodles or needles or, where the die is followed by a blade, granules.